They also asked that a ninth former minister be freed and ordered to pay a bond.
Deposed Catalan leader Carles Puigdemont and four other ministers, however, refused to show up in Madrid as summoned and remain in Belgium.
Puigdemont and 19 others involved in Catalonia's rollercoaster secession push over recent weeks have been summoned to be questioned by Spanish judges in separate hearings at the National Court and the Supreme Court in Madrid on Thursday and Friday.
The first person to be questioned was Jordi Turull, the regional government's former spokesman.
Spain's top prosecutor has filed heavy charges against the toppled leaders of the region of Catalonia for their attempts to secure independence from the country.
"You are not alone," a group of around 30 people, mostly Catalan lawmakers, chanted while former regional ministers, dismissed on Friday as Madrid sought to get a grip on the country's worst crisis in decades, arrived at the National Court.
But illustrating how the situation has fired up emotions around the country of 45 million people - 7.5 million of them in Catalonia - around a dozen opponents of the separatists brandished red-and-yellow Spanish flags, an AFP reporter at the scene said.
Puigdemont's government organised an independence referendum on October 1 - that heavy-handed Spanish police tried and failed to stop - which was followed by a declaration of independence by the Catalan parliament last Friday.
Later that day Spanish Prime Minister Mariano Rajoy's government dismissed the regional government and moved to impose direct rule on the wealthy northeastern region.
On Monday, Spain's chief prosecutor said he was seeking charges of rebellion -- punishable by up to 30 years behind bars -- sedition and misuse of public funds against Puigdemont and 13 associates.
Those who turned up were to be questioned by National Court judge Carmen Lamela who could then charge them and put them in preventive custody.
Puigdemont and the four others who failed to appear could face arrest warrants, international ones if necessary. Puigdemont's lawyer has said he wants his client questioned in Belgium.
The Catalan parliament's speaker and five parliamentary deputies are facing the same charges. All arrived at the Supreme Court on Thursday for their grilling, another AFP reporter said.
"This shouldn't be happening, the conflict between Catalonia and the Spanish state won't be resolved through courts and violence," said former Catalan president Artur Mas, who had travelled to Madrid to show support.
"The more gasoline and wood you add to the fire, the bigger it becomes."
Puigdemont, 54, has dismissed the accusations as politically motivated and on Tuesday said he would remain in Brussels until he had guarantees that any proceedings would be impartial.
In a statement, he said part of his government would go to the National Court "to denounce the drive of Spanish justice to pursue political ideas," while others, including himself, "will stay in Brussels to decry this political process to the international community."
Puigdemont has retained the support of many in Catalonia, whose people are fiercely proud of their language and culture.
Maria Angels Selgas, a 60-year-old sales manager in Barcelona, said that for her, Puigdemont was still the Catalan president.
"If they humiliate him then they humiliate also the more than two million Catalans who voted 'yes' in the referendum," she told AFP.
On Wednesday several hundred separatist supporters accompanied some of those due to appear in the Madrid court to Barcelona's main train station, chanting "liberty" and "you are not alone".
But Catalans remain deeply divided about independence, polls indicate.
The international community has swung firmly behind Rajoy, and uncertainty about Catalonia's future has prompted companies to move their legal headquarters outside the region in droves.
In addition, there are signs of growing divisions in the separatist camp, with many unhappy with Puigdemont and his handling of the situation.
Fernando Vallespin, a political scientist in Madrid, said he believed that Puigdemont, a former journalist, "is more interested in obtaining media attention than escaping justice."
"It's a media war. The aim of (the Catalan executive) has been to try and present the Spanish state as an oppressor state and Puigdemont needs to feed this narrative," he said.
Rajoy has called snap elections for December 21 to replace the Catalan parliament. Puigdemont said he would "respect" the result -- and appealed to Madrid to do the same.